Lightweight airtight cable and processing method thereof

Abstract

The invention belongs to the technical field of light-weight cables, and particularly relates to a light-weight airtight cable and a processing method thereof. According to the invention, the conductor adopts a tinned (bare) compact structure, but the current-carrying capacity is kept unchanged, so that the overall outer diameter and the overall weight of the cable are reduced; the grafting voltage stabilizer is grafted to the cross-linked modified insulating polyolefin prepared from polyethylene, so that the cross-linking degree of the cross-linked polyolefin is maintained, the dosage of the cross-linking agent is reduced, the migration of the voltage stabilizer is inhibited, and the insulating property of the insulating layer is improved; the surface of the filling rope is modified by using an acetone solution of silicone rubber, so that the corrosion resistance and toughness of the surface of the filling rope are enhanced, the blown filling rope does not open a net, the stacking degree is tighter, and the air tightness of the filling layer is improved; when the cable burns, the modified nano magnesium hydroxide can be decomposed to absorb heat, the flame-retardant additive can catalyze the resin to form a carbon layer to block air, and the cable has flame-retardant and smoke-suppressing performance; the cable prepared by the invention has excellent air tightness, insulation, fire resistance and flame retardance.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightweight cables, and particularly relates to a lightweight airtight cable and a processing method thereof. Background Art

[0002] Marine cables are an important part of the ship's power system, responsible for connecting key equipment such as generators, transformers, and switchboards. During the operation of the ship, vibrations and impacts will occur, and these mechanical stresses will damage the cables. Therefore, the cables must have high mechanical strength to withstand mechanical stresses such as vibrations, impacts, and tensile forces during the operation of the ship, and the cables need to be lightweight to reduce the load of the ship and improve the navigation efficiency and fuel economy of the ship. When the cable is applied to a floating production, storage, and offloading unit in the sea and there are harmful gases in the non-safe area, the cable needs to have longitudinal airtightness to prevent the harmful gases from spreading from the non-safe area to the safe area through the cable.

[0003] The Chinese invention patent with the publication number CN119181535B proposes a marine salt spray corrosion-resistant rubber sheathed cable, which sequentially includes a conductor, a fire-resistant layer, an insulating layer, a flame-retardant layer, an armored layer, and a sheath layer from the inside to the outside. The raw materials of the sheath layer include the following components in parts by mass: 100 parts of ethylene propylene diene monomer rubber, 15 - 20 parts of modified kaolin with a modifier, 60 - 80 parts of a flame retardant, 1 - 3 parts of an antioxidant, 1 - 5 parts of a cross-linking agent, 3 - 5 parts of an accelerator. The modified kaolin with a modifier includes a first modified kaolin with a modifier and a second modified kaolin with a modifier in a mass ratio of 1:9 - 9:1. The first modifier in the first modified kaolin with a modifier is a silane coupling agent, and the second modifier in the second modified kaolin with a modifier is an organic amine. Through the above technical solution, the problem of poor salt spray corrosion resistance of the existing marine rubber sheathed cable is solved. The Chinese invention patent with the publication number CN116230298B discloses a halogen-free flame-retardant lightweight ship cable, including a wire, the outside of which is wrapped with a low-smoke halogen-free sheath, the outside of the low-smoke halogen-free sheath is wrapped with a mica tape layer, the outside of the mica tape layer is wrapped with an armored layer, the outside of the armored layer is wrapped with a protective layer, and a protective bracket is arranged inside the low-smoke halogen-free sheath, and the protective bracket is fixedly installed with the wire. For this halogen-free flame-retardant lightweight ship cable and its processing technology of the low-smoke halogen-free sheath, the outside of the metal wire is wrapped with two insulating layers made of different materials, and the two cooperate to ensure the electrical performance of the cable and improve the flame-retardant performance of the cable. The provided mica tape layer can form a dense oxygen isolation layer when on fire, further improving the flame retardancy of the cable. The adopted low-smoke halogen-free sheath is lightweight and has excellent flame-retardant performance, that is, it effectively reduces the overall weight of the cable and can well retard fire. However, the prior art has the technical problem that the insulation and airtightness of the cable are not further improved by improving the composition of the insulating layer and the airtightness of the filler. Summary of the Invention

[0004] The object of the present invention is to provide a lightweight airtight cable and its processing method, which are used to solve the technical problem in the prior art that the insulation and airtightness of the cable are not further improved by further improving the composition of the insulating layer and the airtightness of the filler.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A lightweight airtight cable, from the inside to the outside, includes a conductive core, an inner sheath layer, an armor layer and an outer sheath layer. 3 to 20 conductive cores are annularly arrayed inside the inner circumference of the inner sheath layer, and a filler is filled between the conductive core and the inner sheath layer;

[0007] The conductive core includes a conductor, a fire-resistant layer and an insulating layer from the inside to the outside. The outer diameter of the conductor is 9 to 14 mm, the insulating layer is 1.1 to 1.5 mm, and the outer diameter of the conductive core is 11 to 16.5 mm.

[0008] Optionally, the conductive core further includes an insulation shielding layer and a metal shielding layer outside the insulating layer.

[0009] The material of the insulation shielding layer is a mixture of ethylene-ethyl acrylate resin and conductive carbon black, and the addition amount of conductive carbon black is 40 to 45% of the mass of ethylene-ethyl acrylate resin. The material of the metal shielding layer is copper foil.

[0010] The fire-resistant layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is an unopened filling rope with an outer diameter of 0.03 to 0.04 mm; the inner sheath layer is a low-smoke, halogen-free, flame-retardant polyolefin sheath with the model SHF2; the armor layer is made of tinned copper wire braiding; the outer sheath layer is a low-smoke, halogen-free, flame-retardant, oil-resistant cross-linked polyolefin material.

[0011] A processing method of a lightweight airtight cable includes the following steps:

[0012] S1. Draw a round copper rod through a wire drawing machine, anneal and tin it, and test to obtain qualified copper single wires. After arranging the copper single wires, use a compacting die on a stranding machine to strand and compact while stranding to obtain a conductor;

[0013] S2. Wind the mica tape around the conductor at a winding angle of 45 to 65° to obtain a fire-resistant layer, and uniformly coat the molten cross-linked modified insulating polyolefin on the conductor through an extruder, and air-cool and shape it to obtain a conductive core;

[0014] S3. Stranding 3 to 20 single conductive cores into a cable, and filling the filler in a spiral winding manner;

[0015] S4. The molten low-smoke, halogen-free, flame-retardant polyolefin sheath is evenly coated around the filler by an extruder, and the inner sheath layer is obtained by air-cooling and shaping. The armor layer is made by braiding tinned copper wires. The molten low-smoke, halogen-free, flame-retardant, oil-resistant cross-linked polyolefin material is evenly coated around the armor layer by an extruder, and the outer sheath layer is obtained by air-cooling and shaping. After the cable performance is detected to be qualified, it is packaged for shipment to obtain the lightweight airtight cable.

[0016] Preferably, in S1, the wire-drawing die is selected from a Z-type wire-drawing die and a circular wire-drawing die, and the conductor is made by tightly pressing a Z-type copper single wire wrapped around a cylindrical copper single wire.

[0017] Preferably, in S2, the overlapping rate of mica tape winding is between 30% and 40%.

[0018] Preferably, in S4, the braiding density of the armor layer is greater than 90%.

[0019] The preparation method of the insulating layer material of the cross-linked modified insulating polyolefin includes the following steps:

[0020] S11. By mass, 0.2 - 0.3 parts of N,N-dimethyl-1,2-ethylenediamine and 0.1 - 0.2 parts of cuprous iodide are added to 50 - 100 parts of deionized water. While stirring, 3 - 5 parts of 3,4'-dichlorobenzophenone are added to the system. Nitrogen is introduced, and the temperature is raised to 90 - 100 °C. 2 - 3 parts of 4-methyl-3-pyrrolin-2-one are added, and condensation reaction is carried out at 100 - 105 °C for 24 h. After filtration, activated carbon is added for dehydration for 10 - 12 h, the product is separated by chromatography, and the grafted voltage stabilizer is obtained by rotary evaporation;

[0021] S12. By mass, 95 - 100 parts of polyethylene resin, 1 - 2 parts of nano-zinc oxide, 0.5 - 2 parts of antioxidant and 2 - 4 parts of grafted voltage stabilizer are added to a mixer and mixed for 5 - 10 min. After adding 0.5 - 2 parts of cross-linking agent, the temperature is raised to 105 - 110 °C and stirred for cross-linking for 5 - 10 min to obtain a cross-linked mixture. The cross-linked mixture is added to an extruder to extrude a hot melt. The hot melt is put into a vulcanizer, the temperature is raised to 130 - 160 °C, and hot pressing cross-linking is carried out at a pressure of 5 - 15 Mpa for 20 - 40 min. After cooling, it is put into a vacuum environment at 70 - 80 °C for degassing to obtain the cross-linked modified insulating polyolefin.

[0022] Preferably, the synthesis principle of the grafted voltage stabilizer is as follows:

[0023]

[0024] The mass spectrometry detection results of the grafted voltage stabilizer are as follows: m / z: 372.15 (100.0%), 373.15 (25.2%), 374.15 (3.8%).

[0025] Preferably, the crosslinking agent in S12 is any one of dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0026] Preferably, the model of the polyethylene resin in S12 is any one of 2426H, 19N430, and HMA016, and the antioxidant is one or a combination of more than one of 1010, 168, and 1076.

[0027] Preferably, the temperature of the feed inlet of the extruder in S12 is 110-120°C, and the temperature of the discharge outlet is 130-160°C.

[0028] The preparation method of the non-opening filling rope includes the following steps:

[0029] S21. By mass, add 5-6 parts of nano-zinc oxide powder to 50-60 parts of absolute ethanol, heat up to 30-40°C, and dropwise add a mixed solution of 50-60 parts of vinyl silane coupling agent in deionized water and absolute ethanol under stirring. After the dropping is completed, react for 3-4 h, heat up to 70-80°C, add 8-9 parts of acrylic acid, 1-2 parts of styrene, 1-1.5 parts of methyl acrylate, 1-2 parts of vinyl imidazole, and 0.1-0.3 parts of azobisisobutyronitrile to 30-40 parts of absolute ethanol and then add them to the system, and react at 70-80°C for 4-6 h. Filter by suction to collect the solid, wash it with absolute ethanol, and dry it at 70-80°C to obtain modified nano-zinc oxide powder.

[0030] S22. By mass, mix 95-100 parts of polypropylene, 5-6 parts of modified nano-zinc oxide powder, 0.2-0.3 parts of nucleating agent, and 0.5-2 parts of zinc stearate for 5-10 min, add them into an extruder to extrude a melt for blow molding, put the melt into a mold to extrude a hollow tube blank, blow it up and shape it, soak it in the modifying liquid for 1-2 h after cooling, dry it at room temperature for 12-24 h, cut it and wind it up to obtain the non-opening filling rope.

[0031] Preferably, the vinyl silane coupling agent in S21 is any one of A-151, A-152, and A-173, the mass ratio of nano-zinc oxide powder to vinyl silane coupling agent is 5-6:1-2, and the mass ratio of deionized water to absolute ethanol in the mixed solution of deionized water and absolute ethanol is 1:9.

[0032] Preferably, the polypropylene resin in S22 is any one of HM550H, HM03, and F401. The nucleating agent is prepared by mixing an α-type nucleating agent and a β-type nucleating agent in a mass ratio of 2-3:1. The α-type nucleating agent is any one of sorbitol-based nucleating agents and metal salt phosphate nucleating agents, and the β-type nucleating agent is any one of aromatic amide nucleating agents and rare earth nucleating agents.

[0033] Preferably, the extrusion rate of the melt for blow molding in S22 is 20-30 r / min, and the blow-up ratio for blow molding is 0.8-1.

[0034] Preferably, the modifying liquid in S22 is an acetone solution containing 5-8 wt% silicone rubber, and the silicone rubber is any one of KE-347 and SE 6035.

[0035] The preparation method of the low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin material includes the following steps:

[0036] S31. By mass, add 5-6 parts of 4A zeolite powder to 500-1000 parts of deionized water, ultrasonically treat for 30-40 min, add 0.5-0.8 parts of copper chloride and 5-6 parts of dopamine hydrochloride, stir at a speed of 300-500 r / min for 10-20 min, then add 65-125 parts of tris(hydroxymethyl)aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 30-40 °C for 10-12 h, filter by suction to collect the solid, wash with deionized water, and dry at 50-60 °C to obtain the flame retardant aid.

[0037] S32. By mass, add 5-6 parts of nano magnesium hydroxide to 200-300 parts of absolute ethanol, ultrasonically treat for 20-30 min to obtain a suspension, then add it to 200-300 parts of a 1-2 wt% carboxymethyl chitosan solution, stir at a speed of 500-800 r / min and heat up to 120-130 °C for condensation reflux for 4-6 h, centrifuge and filter to collect the solid, wash with deionized water and absolute ethanol, and freeze-dry at 0-5 °C and grind to obtain modified nano magnesium hydroxide.

[0038] S33. By mass, put 20 - 30 parts of polyethylene resin, 70 - 80 parts of ethylene - vinyl acetate, 3 - 5 parts of polyolefin elastomer, 0.5 - 2 parts of dicumyl peroxide, 0.5 - 2 parts of zinc stearate, and 0.5 - 2 parts of polyethylene wax into a mixer, cross - link at a rotational speed of 1000 - 2000 r / min for 5 - 10 min, then add 3 - 5 parts of modified nano - magnesium hydroxide, 1 - 3 parts of flame - retardant additive, and 1 - 2 parts of antioxidant, mix at a rotational speed of 2000 - 3000 r / min for 5 - 10 min to obtain a mixed material. Put the mixed material into an open mill, mix and wrap the roll at 100 - 110 °C for 5 - 10 min, then add it into a vacuum vulcanizer, raise the temperature to 120 - 150 °C, and cross - link at a pressure of 8 - 10 MPa for 10 - 20 min to obtain a low - smoke, halogen - free, flame - retardant, oil - resistant cross - linked polyolefin material.

[0039] Preferably, the type of polyethylene resin in S33 is any one of 2426H, 19N430, and HMA016; the type of ethylene - vinyl acetate is any one of 7470M, EV180, and EV210ETR; the polyolefin elastomer is any one of C1070D, E226, and C5070D; the antioxidant is one or a combination of more than one of 1010, 168, and 1076.

[0040] In summary, due to the adoption of the above - mentioned technical solutions, the beneficial effects of the present invention are as follows:

[0041] 1. The conductor of the present invention adopts a tinned (bare) compacted structure. The number of single conductors is reduced, the outer diameter of the conductor is decreased, but the current - carrying capacity remains unchanged, reducing the overall outer diameter and overall weight of the cable. When the cable is applied to a narrow laying environment, the space utilization rate can be improved; grafting a voltage stabilizer onto polyethylene to obtain a cross - linked modified insulating polyolefin can maintain the cross - linking degree of the cross - linked polyolefin while reducing the dosage of the cross - linking agent and inhibiting the migration of the voltage stabilizer, improving the insulation performance of the insulating layer; preparing a filling rope from polypropylene and modified zinc oxide through a blowing process, and then modifying the surface of the filling rope with an acetone solution of silicone rubber to enhance the surface corrosion resistance and toughness of the filling rope. The filling rope formed by blowing does not open the net, and the stacking degree is closer, improving the airtightness of the filling layer; the low - smoke, halogen - free, flame - retardant, oil - resistant cross - linked polyolefin material prepared from polyethylene resin, ethylene - vinyl acetate, polyolefin elastomer, modified nano - magnesium hydroxide, and flame - retardant additive has excellent anti - oil pollution and flame - retardant properties. When the cable burns, the modified nano - magnesium hydroxide can decompose and absorb heat, and the flame - retardant additive can catalyze the resin to form a carbon layer to block air, having the performance of flame - retardant and smoke - suppression; the cable prepared by the present invention has excellent airtightness, insulation, fire - resistance, and flame - retardant properties.

[0042] 2. The grafted voltage stabilizer obtained by the grafting reaction of 3,4'-dichlorobenzophenone and 4-methyl-3-pyrrolin-2-one in the present invention has a benzophenone structure, which can absorb high-energy electrons. The conjugated aromatic ring structure can evenly distribute the electric field and inhibit partial discharge. The grafted voltage stabilizer is cross-linked and grafted onto polyethylene, improving the anti-migration performance of the stabilizer. The prepared cross-linked modified insulating polyolefin has excellent voltage stability.

[0043] 3. In the present invention, vinyl silane coupling agent is used to graft nano-zinc oxide, and then acrylic acid, styrene, methyl acrylate and vinyl imidazole are grafted. The prepared modified nano-zinc oxide powder has excellent antioxidant performance and dispersibility; the cyclic structures contained in the grafted styrene and vinyl imidazole improve the wear resistance of the polypropylene filling rope; the acetone solution of silicone rubber modifies the surface of the filling rope, enhancing the surface corrosion resistance and toughness of the filling rope, and improving the tensile strength and antioxidant performance of the polypropylene filling rope.

[0044] 4. The low-smoke, halogen-free, flame-retardant and oil-resistant cross-linked polyolefin material prepared from polyethylene resin, ethylene-vinyl acetate, polyolefin elastomer, modified nano-magnesium hydroxide and flame-retardant auxiliary has excellent anti-oil pollution and flame-retardant properties. The cross-linked polyolefin prepared from polyethylene resin, ethylene-vinyl acetate and polyolefin elastomer has excellent oil resistance; when the cable burns, the modified nano-magnesium hydroxide can decompose and absorb heat, and the flame-retardant auxiliary can catalyze the resin to form a carbon layer to block air, having fire-resistant and flame-retardant and smoke-suppressing properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1 is a schematic cross-sectional view of a lightweight airtight cable of the present invention;

[0047] Figure 2 is a schematic cross-sectional view of another lightweight airtight cable of the present invention;

[0048] Figure 3 is a schematic view of the first conductor structure of a lightweight airtight cable of the present invention;

[0049] Figure 4 is a schematic view of the second conductor structure of a lightweight airtight cable of the present invention;

[0050] Figure 5 is a schematic view of the third conductor structure of a lightweight airtight cable of the present invention;

[0051] Figure 6 It is the first physical diagram of a lightweight airtight cable of the present invention;

[0052] Figure 7 It is the second physical diagram of a lightweight airtight cable of the present invention.

[0053] Reference signs: 1-1 conductor, 1-2 fire-resistant layer, 1-3 insulating layer, 1-4 insulating shielding layer, 1-5 metal shielding layer, 1 conductive core, 2 filler, 3 inner sheath layer, 4 armor layer, and 5 outer sheath layer. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0055] Embodiment 1, refer to Figure 1 、 Figure 6 As shown, a lightweight airtight cable of this embodiment includes, from the inside out, a conductive core 1, an inner sheath layer 3, an armor layer 4, and an outer sheath layer 5. 19 conductive cores are distributed in a circular array around the inner circumference of the inner sheath layer, and a filler 2 is filled between the conductive core and the inner sheath layer;

[0056] The conductive core includes, from the inside out, a conductor 1-1, a fire-resistant layer 1-2, and an insulating layer 1-3. The outer diameter of the conductor is 9 mm, the insulating layer is 1.1 mm, and the outer diameter of the conductive core is 11.5 mm.

[0057] The fire-resistant layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is an unopened filling rope with an outer diameter of 0.04 mm; the inner sheath layer is a low-smoke, halogen-free, flame-retardant polyolefin sheath with the model SHF2; the armor layer is made of tinned copper wire braiding; the outer sheath layer is a low-smoke, halogen-free, flame-retardant, oil-resistant, cross-linked polyolefin material.

[0058] Embodiment 2, refer to Figure 2 、 Figure 7 As shown, the difference between a lightweight airtight cable of this embodiment and that of Embodiment 1 is that it includes, from the inside out, a conductive core 1, an inner sheath layer 3, an armor layer 4, and an outer sheath layer 5. 3 conductive cores are distributed in a circular array around the inner circumference of the inner sheath layer, and a filler 2 is filled between the conductive core and the inner sheath layer;

[0059] The conductive core includes a conductor 1-1, a refractory layer 1-2, an insulating layer 1-3, an insulating shield layer 1-4, and a metal shield layer 1-5 from the inside out. The outer diameter of the conductor is 11 mm, the insulating layer is 1.1 mm, and the outer diameter of the conductive core is 13.2 mm.

[0060] The material of the insulating shield layer is a mixture of ethylene-ethyl acrylate resin and conductive carbon black, and the addition amount of conductive carbon black is 40% of the total weight of the ethylene-ethyl acrylate resin. The material of the metal shield layer is copper foil.

[0061] The refractory layer is a calcined mica tape; the insulating layer is a cross-linked modified insulating polyolefin; the filler is an unopened filling rope with an outer diameter of 0.03 mm; the inner sheath layer is a low-smoke, halogen-free, flame-retardant polyolefin sheath with the model SHF2; the armor layer is made of tinned copper wire braiding; the outer sheath layer is a low-smoke, halogen-free, flame-retardant, oil-resistant cross-linked polyolefin material.

[0062] Example 3, a processing method of a lightweight airtight cable in this example, includes the following steps:

[0063] S1. Draw a round copper rod through a wire drawing machine, anneal and tin it, and after inspection, obtain qualified copper single wires. After arranging the copper single wires, use a compacting die on a stranding machine to strand and compact while stranding to obtain a conductor.

[0064] S2. Wrap the mica tape around the conductor at a winding angle of 45° to obtain a refractory layer. The overlapping rate of the mica tape winding is 35%. Extrude the molten cross-linked modified insulating polyolefin through an extruder, and uniformly coat the molten cross-linked modified insulating polyolefin on the conductor, and air-cool and shape it to obtain a conductive core.

[0065] S3. Stranding 19 single conductive cores into a cable, and the filler is filled in a spiral winding manner.

[0066] S4. Uniformly coat the molten low-smoke, halogen-free, flame-retardant polyolefin sheath around the filler through an extruder, and air-cool and shape it to obtain an inner sheath layer. Use tinned copper wire to braid to obtain an armor layer, and the braiding density is greater than 90%. Uniformly coat the molten low-smoke, halogen-free, flame-retardant, oil-resistant cross-linked polyolefin material around the armor layer through an extruder, and air-cool and shape it to obtain an outer sheath layer. After the cable performance is qualified through inspection, it is packaged and shipped to obtain a lightweight airtight cable.

[0067] The preparation method of the cross-linked modified insulating polyolefin in this example includes the following steps:

[0068] S11. By mass, add 2 g of N,N-dimethyl-1,2-ethylenediamine and 1 g of cuprous iodide to 500 g of deionized water. While stirring, add 20 g of 3,4'-dichlorobenzophenone to the system. Introduce nitrogen gas, heat up to 100 °C, add 10 g of 4-methyl-3-pyrrolin-2-one, and carry out a condensation reaction at 105 °C for 24 h. After filtration, add activated carbon for dehydration for 12 h, separate the product by chromatography, and obtain the grafted voltage stabilizer by rotary evaporation;

[0069] S12. By mass, add 950 g of 2426H polyethylene resin, 10 g of nano-zinc oxide, 10 g of antioxidant 1010, and 20 g of the grafted voltage stabilizer to a mixer and mix for 10 min. After adding 20 g of dicumyl peroxide crosslinking agent, heat up to 110 °C and stir for crosslinking for 10 min to obtain a crosslinked mixture. Add the crosslinked mixture to an extruder to extrude a hot melt. The temperature of the feed inlet of the extruder is 110 °C, and the temperature of the discharge outlet is 130 °C. Put the hot melt into a vulcanizer, heat up to 130 °C, and carry out hot pressing crosslinking at a pressure of 10 Mpa for 20 min. After cooling, put it into a vacuum environment at 80 °C for degassing to obtain crosslinked modified insulating polyolefin.

[0070] The preparation method of the non-opening net filling rope in this embodiment includes the following steps:

[0071] S21. By mass, add 5 g of nano-zinc oxide powder to 50 g of absolute ethanol, heat up to 30 °C, and while stirring, dropwise add 50 g of a mixed solution prepared by dissolving 1 g of A-151 vinyl silane coupling agent in a mixture of deionized water and absolute ethanol with a mass ratio of 1:9. After the dropping is completed, react for 4 h, heat up to 80 °C, add 8 g of acrylic acid, 1 g of styrene, 1.5 g of methyl acrylate, 2 g of vinyl imidazole, and 0.3 g of azobisisobutyronitrile to 40 g of absolute ethanol and then add it to the system, and react at 80 °C for 4 h. Filter to collect the solid, wash it with absolute ethanol, and dry it at 70 °C to obtain modified nano-zinc oxide powder;

[0072] S22. By mass, mix 960 g of F401 polypropylene, 50 g of modified nano-zinc oxide powder, 3 g of nucleating agent, and 5 g of zinc stearate for 5 min. The nucleating agent is prepared by mixing NA-88 sorbitol-based α-type nucleating agent and WBG-II rare earth-based β-type nucleating agent in a mass ratio of 2:1. Add it to an extruder and extrude at an extrusion rate of 25 r / min to obtain a melt for blow molding. Put the melt into a mold to extrude a hollow tube blank, blow it up and shape it, with a blow-up ratio of 1. After cooling, immerse it in the modification liquid for 2 h. The modification liquid is an acetone solution containing 5 wt% KE-347 silicone rubber. Dry it at room temperature for 24 h, cut it and wind it up to obtain the non-opening net filling rope.

[0073] The preparation method of the low-smoke, halogen-free, flame-retardant and oil-resistant crosslinked polyolefin material in this embodiment includes the following steps:

[0074] S31. By mass, add 5 g of 4A zeolite powder to 500 g of deionized water, ultrasonically treat for 30 min, add 0.5 g of copper chloride and 5 g of dopamine hydrochloride, stir at a speed of 500 r / min for 20 min, then add 65 g of tris(hydroxymethyl)aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 40 °C for 12 h, filter to collect the solid, wash with deionized water, and dry at 60 °C to obtain the flame retardant additive;

[0075] S32. By mass, add 5.5 g of nano magnesium hydroxide to 200 g of absolute ethanol, ultrasonically treat for 20 min to obtain a suspension, then add it to 200 g of 1 wt% carboxymethyl chitosan solution, stir at a speed of 500 r / min and heat up to 120 °C for condensation reflux for 6 h, centrifuge and filter to collect the solid, wash with deionized water and absolute ethanol, and freeze-dry at 0 °C and grind to obtain the modified nano magnesium hydroxide;

[0076] S33. By mass, put 200 g of 2426H polyethylene resin, 800 g of 7470M ethylene-vinyl acetate, 30 g of C1070D polyolefin elastomer, 5 g of diisopropylbenzene peroxide, 5 g of zinc stearate and 10 g of polyethylene wax into a mixer, crosslink at a speed of 1000 r / min for 5 min, then add 30 g of modified nano magnesium hydroxide, 15 g of flame retardant additive and 15 g of 1010 antioxidant, mix at a speed of 2000 r / min for 5 min to obtain a mixture, put the mixture into an open mill, knead and wrap the roll at 110 °C for 10 min, then add it to a vacuum vulcanizer, heat up to 120 °C, and crosslink at a pressure of 10 MPa for 20 min to obtain a low-smoke, halogen-free, flame-retardant and oil-resistant crosslinked polyolefin material.

[0077] Example 4. A processing method of a lightweight airtight cable in this example includes the following steps:

[0078] S1. Draw the round copper rod through a wire drawing machine, anneal and tin-plate it, and detect to obtain qualified single copper wires. After arranging the single copper wires, use a compacting die on a stranding machine to strand and compact while stranding to obtain a conductor;

[0079] S2. Wind the mica tape around the conductor at a winding angle of 50° to obtain a fire-resistant layer. The overlapping rate of the mica tape winding is 40%. Extrude the molten crosslinked modified insulating polyolefin through an extruder, and uniformly coat the molten crosslinked modified insulating polyolefin on the conductor, and air-cool and shape it to obtain a conductive core;

[0080] S3. Stranded 3 single conductive cores into a cable, and the filler is wound and filled in a spiral manner;

[0081] S4. Uniformly coat the filler with a molten low-smoke, halogen-free, flame-retardant polyolefin sheath through an extruder, and obtain the inner sheath layer by air-cooling and shaping. Manufacture the armor layer by braiding tinned copper wires, with a braiding density greater than 90%. Uniformly coat the armor layer with a molten low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin material through an extruder, and obtain the outer sheath layer by air-cooling and shaping. After the cable performance is tested and qualified, package it for shipment to obtain the lightweight airtight cable.

[0082] The crosslinked modified insulating polyolefin in this example is different from that in Example 3 in that the type of polyethylene resin is replaced by HMA016, and the oxidant is replaced by a mixture of 1010 and 168 in a mass ratio of 1:1.

[0083] The preparation methods of the non-opening filling rope and the low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin material in this example are the same as those in Example 3.

[0084] Example 5. A processing method for a lightweight airtight cable in this example includes the following steps:

[0085] S1. Draw a round copper rod through a wire drawing machine, anneal and tin it, and obtain qualified copper single wires after testing. After arranging the copper single wires, use a compacting die on a stranding machine to strand and compact them simultaneously to obtain a conductor.

[0086] S2. Wrap the mica tape around the conductor at a wrapping angle of 60° to obtain a fire-resistant layer, with a mica tape wrapping overlap rate of 33%. Extrude a molten crosslinked modified insulating polyolefin through an extruder, and uniformly coat the molten crosslinked modified insulating polyolefin on the conductor, and obtain the conductive core by air-cooling and shaping.

[0087] S3. Stranded 19 single conductive cores into a cable, and the filler is filled in a spiral winding manner.

[0088] S4. Uniformly coat the filler with a molten low-smoke, halogen-free, flame-retardant polyolefin sheath through an extruder, and obtain the inner sheath layer by air-cooling and shaping. Manufacture the armor layer by braiding tinned copper wires, with a braiding density greater than 90%. Uniformly coat the armor layer with a molten low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin material through an extruder, and obtain the outer sheath layer by air-cooling and shaping. After the cable performance is tested and qualified, package it for shipment to obtain the lightweight airtight cable.

[0089] The difference between the non-opening filling rope in this example and that in Example 3 is that the nucleating agent is prepared by mixing NA-21 metal salt of phosphate ester nucleating agent and TMB-5 aromatic amide nucleating agent in a mass ratio of 2:1.

[0090] The preparation methods of the crosslinked modified insulating polyolefin and the low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin material in this example are the same as those in Example 3.

[0091] Example 6. A processing method for a lightweight airtight cable in this example includes the following steps:

[0092] S1. Draw a round copper rod through a wire drawing machine, anneal and tinplate it, and obtain qualified copper single wires through detection. After arranging the copper single wires, use a compacting die on a stranding machine to strand and compact them simultaneously to obtain a conductor.

[0093] S2. Wrap the mica tape around the conductor at a wrapping angle of 65° to obtain a fire-resistant layer. The double-layer overlapping rate of the mica tape wrapping is 30%. Extrude the molten crosslinked modified insulating polyolefin through an extruder, and evenly coat the molten crosslinked modified insulating polyolefin on the conductor, and air-cool and shape it to obtain a conductive core.

[0094] S3. Strand 20 single conductive cores into a cable, and fill it with a filler in a spiral winding manner.

[0095] S4. Evenly coat the molten low-smoke, halogen-free, flame-retardant polyolefin sheath around the filler through an extruder, air-cool and shape it to obtain an inner sheath layer. Use tinned copper wire to braid to obtain an armor layer, and the braiding density is greater than 90%. Evenly coat the molten low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin around the armor layer through an extruder, air-cool and shape it to obtain an outer sheath layer. After detecting that the cable performance is qualified, perform factory packaging to obtain a lightweight airtight cable.

[0096] The difference between the low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin in this example and that in Example 3 is that the model of the polyethylene resin is replaced with 19N430, and the model of ethylene-vinyl acetate is replaced with EV180.

[0097] The preparation methods of the crosslinked modified insulating polyolefin and the non-woven filling cord in this example are the same as those in Example 3.

[0098] Comparative Example 1. The difference between this comparative example and Example 3 is that the grafted voltage stabilizer of the crosslinked modified insulating polyolefin is replaced with 4,4'-dihydroxybenzophenone.

[0099] Comparative Example 2. The difference between this comparative example and Example 3 is that the non-woven filling cord is replaced with a woven filling cord.

[0100] Comparative Example 3. The difference between this comparative example and Example 3 is that the low-smoke, halogen-free, flame-retardant, oil-resistant crosslinked polyolefin is replaced with crosslinked polyethylene.

[0101] Performance Test

[0102] The conductor and the conventional conductor structure prepared in Example 3 are shown in Figures 3 - 5 as shown. Detect the conductor outer diameter, insulation layer thickness, and approximate outer diameter of the conductor prepared in Example 3 and the conventional conductor. The test results are shown in Table 1:

[0103] Table 1 Conductor Structure

[0104]

[0105]

[0106] According to IEC60079-14 standard, cut 0.5 m of the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3, apply compressed air exceeding the atmospheric pressure by 0.3 kPa at one end, and measure the overpressure value decline rate within 5 s.

[0107] According to IEC60331 standard as shown in Table 2 below, test the fuse melting phenomenon of the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3 under 830 °C flame burning and impact vibration (the interval of impact vibration does not exceed 5 min) within 120 min (the cumulative impact vibration is 36 times).

[0108] Table 2 IEC60331 standard

[0109]

[0110] According to IEC60092-350 standard, use IRM902 mineral oil and IRM903 fuel oil to age the lightweight airtight cables prepared in Examples 3 to 6 and Comparative Examples 1 to 3 at 100 °C for 24 h, and test the change rate of tensile strength and the change rate of elongation at break.

[0111] The test results are shown in Table 3 below:

[0112] Table 3 Test results

[0113]

[0114]

[0115] It can be seen from the data in Table 1 that both the conductor outer diameter and the approximate outer diameter of Example 3 of the present invention are smaller than those of the conventional conductor, indicating that the lightweight airtight cable prepared by the present invention reduces the overall outer diameter of the cable and can improve the space utilization rate.

[0116] As can be seen from the data in Table 2, the overpressure value decline rate of the lightweight airtight cables in Examples 3 to 6 of the present invention is between 13% and 16%. Replacing the non-open mesh filling cord in Comparative Example 2 with an open mesh filling cord results in a decrease in the airtightness of the filler. Therefore, its overpressure value decline rate is 28%, which is much greater than that of Examples 3 to 6, indicating that the lightweight airtight cable prepared by the present invention has excellent airtightness; in Examples 3 to 6 of the present invention, under the conditions of being burned in an 830°C flame and subjected to impact vibration (the interval between impact vibrations does not exceed 5 minutes), the conductive condition is good within 120 minutes (the cumulative impact vibration is 36 times) and the fuse does not blow, indicating that the lightweight airtight cable prepared by the present invention has excellent fire resistance, flame retardancy and insulation properties; after aging treatment, the tensile strength change rate of the lightweight airtight cables in Examples 3 to 6 is 17% to 20%, and the elongation at break change rate is 20% to 22%, indicating that the lightweight airtight cable prepared by the present invention has excellent oil resistance.

[0117] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

[0118] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific embodiments. Obviously, according to the content of this specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A lightweight airtight cable, characterized in that, From the inside out, it includes a conductive core, an inner sheath layer, an armor layer, and an outer sheath layer. A plurality of conductive cores are distributed in an annular array around the inner circumference of the inner sheath layer, and a filler is filled between the conductive cores and the inner sheath layer. The conductive core includes a conductor, a refractory layer, and an insulating layer from the inside out. The outer diameter of the conductor is 9 - 14 mm, the insulating layer is 1.1 - 1.5 mm, and the outer diameter of the conductive core is 11 - 16.5 mm.

2. The lightweight airtight cable according to claim 1, wherein, The conductive core also includes an insulation shielding layer and a metal shielding layer outside the insulating layer. The material of the insulation shielding layer is a mixture of ethylene - ethyl acrylate resin and conductive carbon black, and the addition amount of conductive carbon black is 40 - 45% of the mass of ethylene - ethyl acrylate resin. The material of the metal shielding layer is copper foil; the refractory layer is a calcined mica tape; the insulating layer is a cross - linked modified insulating polyolefin; the filler is an unopened filling rope with an outer diameter of 0.03 - 0.04 mm; the inner sheath layer is a low - smoke, halogen - free, flame - retardant polyolefin sheath; the armor layer is made of tinned copper wire braiding; the outer sheath layer is a low - smoke, halogen - free, flame - retardant, oil - resistant cross - linked polyolefin material.

3. The lightweight airtight cable according to claim 2, characterized in that, The preparation method of the insulating layer material of the cross - linked modified insulating polyolefin includes the following steps: S11: By mass, add 0.2 - 0.3 parts of N,N - dimethyl - 1,2 - ethylenediamine and 0.1 - 0.2 parts of cuprous iodide into 50 - 100 parts of deionized water. Under stirring, add 3 - 5 parts of 3,4’ - dichlorobenzophenone into the system, introduce nitrogen, heat up to 90 - 100 °C, add 2 - 3 parts of 4 - methyl - 3 - pyrrolin - 2 - one, carry out a condensation reaction at 100 - 105 °C for 24 h, filter, then add activated carbon for dehydration for 10 - 12 h, chromatographically separate the product, and rotary evaporate to obtain a grafted voltage stabilizer. S12: By mass, add 95 - 100 parts of polyethylene resin, 1 - 2 parts of nano - zinc oxide, 0.5 - 2 parts of antioxidant, and 2 - 4 parts of grafted voltage stabilizer into a mixer and mix for 5 - 10 min. After adding 0.5 - 2 parts of cross - linker, heat up to 105 - 110 °C and stir - crosslink for 5 - 10 min to obtain a cross - linked mixture. Add the cross - linked mixture into an extruder to extrude a hot melt. Put the hot melt into a vulcanizer, heat up to 130 - 160 °C, and hot - press cross - link at a pressure of 5 - 15 Mpa for 20 - 40 min. After cooling, put it into a vacuum environment at 70 - 80 °C for degassing to obtain the cross - linked modified insulating polyolefin.

4. The lightweight airtight cable according to claim 3, wherein In S12, the cross - linker is any one of diisopropyl peroxide, di - tert - butyl peroxide, and 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, and the antioxidant is one or a combination of 1010, 168, and 1076. The feeding port temperature of the extruder is 110 - 120 °C, and the discharging port temperature is 130 - 160 °C.

5. A lightweight airtight cable according to claim 2, characterized in that, The preparation method of the unopened filling rope includes the following steps: S21. By mass parts, add 5 - 6 parts of nano - zinc oxide powder into 50 - 60 parts of absolute ethanol, heat up to 30 - 40 °C, and under stirring, dropwise add a mixed solution of deionized water and absolute ethanol of 50 - 60 parts of vinyl silane coupling agent. After the dropping is completed, react for 3 - 4 h, then heat up to 70 - 80 °C. Add 8 - 9 parts of acrylic acid, 1 - 2 parts of styrene, 1 - 1.5 parts of methyl acrylate, 1 - 2 parts of vinyl imidazole, and 0.1 - 0.3 parts of azodiisobutyronitrile into 30 - 40 parts of absolute ethanol and then add it into the system. React at 70 - 80 °C for 4 - 6 h, filter by suction to collect the solid, wash it with absolute ethanol, and dry it at 70 - 80 °C to obtain modified nano - zinc oxide powder; S22. By mass parts, mix 95 - 100 parts of polypropylene, 5 - 6 parts of modified nano - zinc oxide powder, 0.2 - 0.3 parts of nucleating agent, and 0.5 - 2 parts of zinc stearate for 5 - 10 min, add them into an extruder to extrude to obtain a melt for blow - molding. Put the melt into a mold to extrude to obtain a hollow tube blank, blow it up and shape it, cool it, then immerse it in a modified liquid for 1 - 2 h, dry it at room temperature for 12 - 24 h, cut it and wind it up to obtain a non - meshed filling rope.

6. The lightweight airtight cable according to claim 1, characterized in that, In S21, the mass ratio of nano - zinc oxide powder to vinyl silane coupling agent is 5 - 6:1 - 2, and the mass ratio of deionized water to absolute ethanol in the mixed solution of deionized water and absolute ethanol is 1:9; in S22, the nucleating agent is prepared by mixing α - type nucleating agent and β - type nucleating agent according to a mass ratio of 2 - 3:

1. The α - type nucleating agent is any one of sorbitol - type nucleating agent and metal salt of phosphate ester nucleating agent, and the β - type nucleating agent is any one of aromatic amide - type nucleating agent and rare - earth - type nucleating agent. The extrusion rate of the melt for blow - molding is 20 - 30 r / min, the blow - up ratio of blow - molding is 0.8 - 1, and the modified liquid is an acetone solution containing 5 - 8 wt% silicone rubber.

7. The lightweight airtight cable according to claim 2, characterized in that, The preparation method of the low - smoke, halogen - free, flame - retardant and oil - resistant cross - linked polyolefin material includes the following steps: S31. By mass parts, add 5 - 6 parts of 4A zeolite powder into 500 - 1000 parts of deionized water, perform ultrasonic treatment for 30 - 40 min, add 0.5 - 0.8 parts of copper chloride and 5 - 6 parts of dopamine hydrochloride, stir at a speed of 300 - 500 r / min for 10 - 20 min, then add 65 - 125 parts of tris (hydroxymethyl) aminomethane, adjust the pH to 8.5 with hydrochloric acid and ammonia water, stir at 30 - 40 °C for 10 - 12 h, filter by suction to collect the solid, wash it with deionized water, and dry it at 50 - 60 °C to obtain a flame - retardant aid; S32. By mass parts, add 5 - 6 parts of nano - magnesium hydroxide into 200 - 300 parts of absolute ethanol, perform ultrasonic treatment for 20 - 30 min to obtain a suspension, then add it into 200 - 300 parts of 1 - 2 wt% carboxymethyl chitosan solution, stir at a speed of 500 - 800 r / min and heat up to 120 - 130 °C for condensation reflux for 4 - 6 h, centrifuge and filter to collect the solid, wash it with deionized water and absolute ethanol, and then freeze - dry it at 0 - 5 °C and grind it to obtain modified nano - magnesium hydroxide; S33. By mass, put 20 - 30 parts of polyethylene resin, 70 - 80 parts of ethylene - vinyl acetate, 3 - 5 parts of polyolefin elastomer, 0.5 - 2 parts of dicumyl peroxide, 0.5 - 2 parts of zinc stearate, and 0.5 - 2 parts of polyethylene wax into a mixer, cross - link for 5 - 10 min, then add 3 - 5 parts of modified nano - magnesium hydroxide, 1 - 3 parts of flame - retardant additive, and 1 - 2 parts of antioxidant, mix for 5 - 10 min to obtain a mixed material. Put the mixed material into an open mill, mix and wrap the roll at 100 - 110 °C for 5 - 10 min, then add it into a vacuum vulcanizer, heat up to 120 - 150 °C, cross - link at a pressure of 8 - 10 MPa for 10 - 20 min to obtain a low - smoke, halogen - free, flame - retardant, oil - resistant cross - linked polyolefin material.

8. A lightweight airtight cable according to claim 7, characterized in that, In the above - mentioned S33, the antioxidant is one or a combination of 1010, 168, and 1076.

9. A processing method of a lightweight airtight cable, characterized in that, It includes the following steps: S1. Draw a round copper rod through a wire - drawing machine, anneal and tin - plate it, and detect to obtain qualified copper single wires. After arranging the copper single wires, use a compacting die on a stranding machine to strand and compact simultaneously to obtain a conductor. S2. Wind the mica tape around the conductor at a winding angle of 45 - 65° to obtain a fire - resistant layer, and evenly coat the molten cross - linked modified insulating polyolefin on the conductor through an extruder, and air - cool and shape it to obtain a conductive core. S3. Stranded multiple single conductive cores into a cable, and the filler is wound and filled in a spiral manner. S4. Evenly coat the molten low - smoke, halogen - free, flame - retardant polyolefin sheath around the filler through an extruder, air - cool and shape it to obtain an inner sheath layer. Use tinned copper wires to braid to obtain an armor layer. Evenly coat the molten low - smoke, halogen - free, flame - retardant, oil - resistant cross - linked polyolefin material around the armor layer through an extruder, air - cool and shape it to obtain an outer sheath layer. After detecting that the cable performance is qualified, package it for factory shipment to obtain a lightweight airtight cable.

10. The processing method of a lightweight airtight cable according to claim 9, characterized in that, In the above - mentioned S1, the conductor is obtained by tightly pressing a Z - type copper single wire wrapped around a cylindrical copper single wire; in the above - mentioned S2, the overlapping rate of the mica tape winding is between 30 - 40%; in the above - mentioned S4, the braiding density of the armor layer is greater than 90%.

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